Structure and Identity of 4,4'-Thiobisbenzenethiol Self-Assembled Monolayers
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- 作者：Yuling Wang ; Linfeng Gan ; Hongjun Chen ; Shaojun Dong ; Jin Wang
- 刊名：Journal of Physical Chemistry B
- 出版年：2006
- 出版时间：October 19, 2006
- 年：2006
- 卷：110
- 期：41
- 页码：20418 - 20425
- 全文大小：387K
- 年卷期：v.110,no.41(October 19, 2006)
- ISSN：1520-5207
文摘
Self-assembled monolayers (SAMs) of 4,4'-thiobisbenzenethiol (TBBT) can be formed on Au surfacespontaneously. The structural characteristics and adsorption behavior of TBBT SAMs on Au have beeninvestigated by surface enhanced Raman scattering (SERS), electrochemical cyclic voltammetry (CV), acimpedance spectroscopy (EIS), and atomic force microscopy (AFM). It is demonstrated that TBBT adsorbedon Au by losing a H atom, forming one Au-S bond, and the other mercapto group is free at the surface ofthe monolayer owing to the presence of the 
S-H at 2513 cm-1 and the 
C-S-H at 910 cm-1 in SERS. Theenhancement of the vibration of C-S (1064 cm-1), the aromatic C-H vibration (3044 cm-1), and the absenceof the vibration of S-S illustrate TBBT adsorbed on Au forming a monolayer with one benzene ring tiltedwith respect to the Au surface. The interpretation of the observed frequencies is aided by ab initio molecularorbital (MO) calculations at the HF/6-31G* level of theory. Electrochemical CV and EIS indicate TBBTmonolayers can passivate the Au effectively for its low ratio of pinhole defects (
= 99.6%). AFM studiesgive details about the surface morphology. The applications of TBBT SAMs have been extensively investigatedby exposure of Cu2+ ion to TBBT SAMs on Au and covalent adsorption of metal nanoparticles. Electrochemical,X-ray photoelectron spectroscopic, and SERS results indicate that Cu2+ can react with TBBT SAMs andpresent on TBBT SAMs as Cu(I). A scanning electron microscopic image of Ag nanoparticles on TBBT/Auand the Raman spectrum of TBBT in smooth macroscopic Au/TBBT SAMs/Ag nanoparticle sandwich structureindicate that metal nanoparticles can be adsorbed on TBBT SAMs effectively through covalent linkage.
S-H at 2513 cm-1 and the C-S-H at 910 cm-1 in SERS. Theenhancement of the vibration of C-S (1064 cm-1), the aromatic C-H vibration (3044 cm-1), and the absenceof the vibration of S-S illustrate TBBT adsorbed on Au forming a monolayer with one benzene ring tiltedwith respect to the Au surface. The interpretation of the observed frequencies is aided by ab initio molecularorbital (MO) calculations at the HF/6-31G* level of theory. Electrochemical CV and EIS indicate TBBTmonolayers can passivate the Au effectively for its low ratio of pinhole defects ( = 99.6%). AFM studiesgive details about the surface morphology. The applications of TBBT SAMs have been extensively investigatedby exposure of Cu2+ ion to TBBT SAMs on Au and covalent adsorption of metal nanoparticles. Electrochemical,X-ray photoelectron spectroscopic, and SERS results indicate that Cu2+ can react with TBBT SAMs andpresent on TBBT SAMs as Cu(I). A scanning electron microscopic image of Ag nanoparticles on TBBT/Auand the Raman spectrum of TBBT in smooth macroscopic Au/TBBT SAMs/Ag nanoparticle sandwich structureindicate that metal nanoparticles can be adsorbed on TBBT SAMs effectively through covalent linkage.